Obstetric ultrasound is one of the most common ultrasound applications, used throughout pregnancy to evaluate the developing fetus, placenta, amniotic fluid, and uterus. First trimester scans establish gestational age and detect early complications. The standard second trimester anatomic survey (typically performed at 18–22 weeks) evaluates fetal anatomy, biometry, placental location, and amniotic fluid volume. Third trimester scans assess fetal growth, presentation, and biophysical profile. Obstetric sonography is a core specialty for RDMS candidates.